Why do we need BUP files?

[AlanHK]

I know that BUP files are "backups of IFO files". But why do we need these?

If the IFOs are unreadable, it's unlikely the rest of the disk is going to be of any use, I think.

I just authored a disk and the files totalled just over 4,700,000,000. So as an experiment I deleted the BUP files to save a half meg, the burning app gave me warnings but I went ahead. The DVD was readable and seems to work fine in my player.

[PTsniper]

wow,

i gess I'll never record a DVD with BUP files again.

I never understood what does BUP do, and I didn't even knew that they were backups of the IFO files.

Thanks man.

[adam]

DVD video has error checking built into the format. You can get a scratch on the disc resulting in read errors for a vob file and yet it can still play, often without even any noticable problems. There's a certain amount of redundancy inherant in mpeg. But IFO files don't have this same error tolerance so if its damaged at all its probably useless and there goes playback for the whole disc. The BUP files are physically stored on a different part of the disc so in the off chance you damage an IFO, you'll likely have the BUP file intact. But I'd say its definitely conceivable that a scratch could corrupt the IFO yet leave the rest of the disc playable so long as the BUP was ok.

Omitting the BUP files will have no effect on playback unless one of the IFO's is damaged. But if that happens you need the BUP or the disc is fubar.

[SLK001]

Plus, a DVD-R can burn ~4,706,000,000 bytes. Also, NERO 6 claims to be able to overburn a DVD by about 10 to 12 MBytes (up to 4,718,592,000 bytes), but I haven't tried to use it yet. It might be able to overburn even further (has anyone here tried this yet?) depending on your blank.

I agree with adam that deleting the .BUP files isn't a desireable action. There also may be players out there that will refuse to play a DVD without them.

[PTsniper]

Well, there is a very good point in there:

I had 3 scratched DVD's (with deeps scratches), but I managed to recover 100% of the DVD's, this thanks to the BUP files i suppose.

[AlanHK]

Well, there is a very good point in there:

I had 3 scratched DVD's (with deeps scratches), but I managed to recover 100% of the DVD's, this thanks to the BUP files i suppose.

I don;t think the BUPs would have made much difference. You can use lots of tools to recover just from the VOB files, which contain the video, audio and subtitles. It's playing it as is that night nake a difference.

Anyway, though my set worked without BUPs, I used Rejig to squeeze some of the video by 1%, which gave me a VIDEO_TS set with no error messages.

[redwudz]

On a DVD I checked at random, the BUP files were 16K - 62K and the IFOs were 16 - 38K. A average burned DVD is 4582277K, if my conversion is correct.

You wouldn't gain much by deleting them as far as DVD space, but you will likely produce a DVD that may not play. I would leave the DVD format alone and just shrink your VOBs down if you need a smaller filesize.

[PTsniper]

lol

yeap, I won't do anything in the DVD.

I've learned.

[AlanHK]

On a DVD I checked at random, the BUP files were 16K - 62K and the IFOs were 16 - 38K. A average burned DVD is 4582277K, if my conversion is correct.

You wouldn't gain much by deleting them as far as DVD space, but you will likely produce a DVD that may not play. I would leave the DVD format alone and just shrink your VOBs down if you need a smaller filesize.

As I said, my original fileset wouldn't fit (see below), omitting the BUPS saved 274,432 bytes and gave a working disk.

It's obviously not very common to be in that narrow range when this would work, but if you don't have the time or inclination (a disk you only want to watch once or twice) to shrink, it's quick fix.

VIDEO_TS.BUP       16,384         
VIDEO_TS.IFO       16,384         
VIDEO_TS.VOB       90,112         
VTS_01_0.BUP       43,008         
VTS_01_0.IFO       43,008         
VTS_01_0.VOB       75,776         
VTS_01_1.VOB  799,571,968         
VTS_02_0.BUP       43,008         
VTS_02_0.IFO       43,008         
VTS_02_0.VOB       75,776         
VTS_02_1.VOB  762,759,168         
VTS_03_0.BUP       38,912         
VTS_03_0.IFO       38,912         
VTS_03_0.VOB       75,776         
VTS_03_1.VOB  671,188,992         
VTS_04_0.BUP       45,056         
VTS_04_0.IFO       45,056         
VTS_04_0.VOB       75,776         
VTS_04_1.VOB  830,625,792         
VTS_05_0.BUP       43,008         
VTS_05_0.IFO       43,008         
VTS_05_0.VOB       75,776         
VTS_05_1.VOB  790,874,112         
VTS_06_0.BUP       45,056         
VTS_06_0.IFO       45,056         
VTS_06_0.VOB       75,776         
VTS_06_1.VOB  843,847,680         
                                  
28 File(s)  4,699,961,344 bytes   
                                  
VIDEO_TS.BUP       16,384         
VTS_01_0.BUP       43,008         
VTS_02_0.BUP       43,008         
VTS_03_0.BUP       38,912         
VTS_04_0.BUP       45,056         
VTS_05_0.BUP       43,008         
VTS_06_0.BUP       45,056         
                                  
total BUPs        274,432